At least 2% of everyone you meet won't like you, it's nothing you've done it's just the way it is, if you have someone who you just don't get on with or doesn't get on with you, pop them in the 2% bucket, you can't please everybody so why try?

You might also want to look into some self-esteem building techniques, I used to care about everything people said to me, since I pumped my self esteem up to a healthy level most comments just wash over me like water off a ducks back.

I actually found that in alot cases the insults were meant as friendly banter but I took every one to heart and whenever anyone gave me a compliment I dismissed it as a one off comment or as a way of getting something from me, never once did I think it was a genuine compliment with no ulterior motive.